Guillotine shears

ABSTRACT

The invention discloses an impact shears having a rotor with individual chopping blades disposed on the rotor in a predetermined arrangement and with blade(s) or blade system that is generally stationary vis-à-vis the rotation of the rotor. The blade is held in a blade holder on the stator side of the rotor. The blade holder is movable on the stator about an axis parallel to the rotational axis of the rotor and carries at least two blades, or blade systems, that are expediently disposed at the same angular distance to one another. The blade holder can be rotated about an axis that extends parallel to the rotational axis of the rotor so that every blade of the blade holder can be brought in a cutting position to interact with the chopping blades of the rotor and can be locked in position with respect to the chopping blades.

[0001] The invention relates to an impact shears with a rotor equipped with individual chopping blades in a predetermined configuration and with at least one blade or blade configuration held in a blade holder, fundamentally stationary relative to the rotational movement of the rotor and disposed at the stator side relative to the rotor, wherein the blade holder is movable about an axis parallel to the rotational axis of the rotor relative to the stator.

[0002] Impact shears are employed for example in the field of recycling for the fine grinding of material already coarsely ground. Coarse grinding of recyclable objects takes place for example by a rotor shears. Such known impact shears comprises a motor-driven rotor, carrying a multiplicity of individual chopping blades. During operation of the impact shears for grinding the particular desired material the blades cooperate with a stationary blade held at the stator side, or they cooperate with a blade configuration formed of blades disposed in series, which blades or blade configuration extend over the entire length of the rotor. The blade of the stator is held in bolt-connection in a blade holder, wherein it is provided that the blade holder can be set up in the radial direction with respect to the rotational axis of the rotor equipped with the chopping blades, in order not only to set primarily the cutting gap but also in order to be able to reset the cutting gap after a blade has been worn out. For this purpose the blade is in bolt-connection with the blade holder and consequently fixed in its position while the blade holder can be set via several set screws relative to the stator in the above described direction. DE 195 14 951 C2 discloses a waste grinder in which the setting of the cutting gap takes place by utilization of an eccentric, which is simplified compared to the application of several set screws. In the case of a change of the stationary blade, the blade must be removed from the blade holder and be replaced by a new one. In addition, the cutting gap between the new blade and the chopping blades on the rotor must be newly set. In particular in the case of a grinding of a very hard material, the wear-and-tear of the stationary blade is so high that it must be changed several times a week. Such a replacement of the blade is time consuming. In particular, during this time the impact shears is under stand down. In order to extend the changing intervals, the settability of the cutting gap has been provided since such a cutting gap resetting can be carried out in shorter time, compared with the time period required for a blade replacement. However, tolerated is in such a measure that after a cutting gap resetting, cutting takes place with dull blades, which under some circumstances can have a disadvantageous effect on the desired cutting result. Moreover, in the case of operating an impact shears with dull blades, the danger exists that it is overloaded which can lead to the blocking of the rotor. For this purpose, in a chip breaker according to DE 43 28 506 C1 it is provided to dispose the blade holder pivotably about an axis parallel to the rotational axis of the rotor at the upper end of a rotating shaft in order to be able to provide through this measure an outside engagement position relative to the chopping blades of the rotor. This outside engagement position of the stator-side blade relative to the chopping blades of the rotor takes place under formation of a coarse scale outlet as overload safety feature if a selectable cutting resistance has been exceeded, such that such objects which cannot be ground can be immediately brought out of the cutting gap without the rotor needing to be stopped.

[0003] Building on this discussed prior art the invention addresses the problem of providing an impact shears of the above described type in which the service life is increased and a blade change is facilitated.

[0004] This problem is solved according to the invention thereby that the blade holder carries at least two blades, usefully disposed at a mutually equal angular distance with respect to one another, or a blade configuration and is rotatable about the axis extending parallel to the rotational axis of the rotor, such that each blade or each blade configuration of the blade holder can be brought into cutting position cooperating with the chopping blades of the rotor and in the cutting position one blade or one blade configuration cooperates with the chopping blades of the rotor and in this position each blade or each blade configuration can be secured in position with respect to the cooperation with the chopping blades of the rotor.

[0005] The impact shears according to the invention provides that the blade holder comprises at least two blades or blade configurations disposed with respect to one another at an angular distance usefully disposed at like angular distance with respect to one another. The blade holder is rotatable about an axis extending parallel to the rotational axis of the rotor such that it is possible for in each instance one of the blades or of the blade configurations of the blade holder to be in its cutting position and consequently cooperating with the chopping blades of the rotor. Consequently, without large expenditures and utilizing the rotatability of the blade holder, only by rotating the blade holder from its cutting position a worn out blade can be brought out of its cutting position and the second blade be brought into cutting position. The actual replacement of the individual blades with a new one can be scheduled for a point in time at which the impact shears is nonoperational in any event. In this case all blades of the blade holder are exchanged in one process. It can further be provided that an exchange of the blade not in its cutting position is carried out even while the impact shears is in operation while a further blade carried by this blade holder is in its cutting position. The blade holder is securable in position relative to the stator in that position in which a blade is in its cutting position such that during operation of the impact shears a transmission of the rotational movement of the rotor via its chopping blades and the material to be ground does not lead to the swivelling of the blade holder.

[0006] To bring about the desired rotatability of the blade holder it can have at both of its ends one pivot pin each, which is set into a bearing groove extending usefully horizontally and starting in a front side of the stator from the outer lateral margin.

[0007] For securing in position the blade holder against a rotational movement and for dissipating the forces acting onto the blade holder during operation of the impact shears, a support arm can be provided pivotably articulated on the stator and stayed on the blade holder, that the support arm at whose free end is disposed the blade holder, is disposed pivotably with respect to the rotor, such that the entire blade holder can be swivelled away from the rotor. This can be utilized for the purpose of being able to carry out a cutting gap setting. Such a cutting gap setting can be provided for example by utilizing an eccentric or also a corresponding set screw acting onto the support arm.

[0008] The support arm can also serve to be part of an overload safety feature. In this case the support arm is articulated usefully via a bolt having a rated breaking point. When the provided cutting force is exceeded, the bolt having the rated breaking point breaks and the blade holder pivots away from the rotor and damage to the blades or chopping blades is avoided.

[0009] In a further implementation it can be provided that an overload safety feature is provided in such manner that upon detecting an overload, the drive of the impact shears is automatically switched off or also that the rotatability of the blade holder is utilized to rotate the blade in the cutting position or the blade configuration in the cutting position is rotated out of its cutting position cooperating with the chopping blades of the rotor to increase the cutting gap.

[0010] A useful further development provides that, apart from the previously described stator-side blade holder, the impact shears comprises a further correspondingly developed blade holder, which, for example, is disposed at the stator side for example mirror-symmetrically to the vertical center plane of the rotor. In particular, the swivellability of an additional configuration of such blade holder is advantageous, since in this position at the rear end of the screen otherwise the accessibility to the blade(s) would hardly be possible. Due to the lower forces acting onto the blade in its cutting position of the blade holder, a torsion tight securing in position of the second blade holder can take place through fitting pins having a rated breaking point, which extend through the stator at the front side and engage fixing cheeks associated in the blade holder. For the facilitated material feeding, with each blade of the second blade holder a flow wedge is associated which is usefully disposed such that it is pivotable, through which the material guided through the rotation of the rotor is guided into the cutting gap.

[0011] According to a further embodiment example the impact shears comprises also two blade holders in the above described configuration. In contrast to the previously described embodiment example the two stator-side blade holders of this embodiment example are developed identically such that the second blade holder is also secured in position torsion tight at the frame side via a support arm.

[0012] If a securement in position of the blade holders via such a support arm is provided, it is useful to form the frame-side or stator-side articulation such that a cutting gap setting can take place. This can be completed thereby that the frame-side articulation takes place via an eccentric.

[0013] According to a further implementation the rotatable blade holder is supported directly on the frame of the impact shears and can be rotated by means of a stepping motor into its different positions. In this embodiment example it is provided in the case of an overload condition that an immediate machine stop is brought about in order to prevent damage to the blade.

[0014] If two blade holders are provided it is useful for increasing the service life of the employed stator-side blades if the two blade holders have overall such number of blades or blade configurations as corresponds to the number of series of the chopping blades disposed on the rotor. In such an implementation a stator-side blade change only needs to be carried out if the chopping blades disposed on the rotor also need to be replaced, even if fundamentally the stator-side blades, which are not in cutting position, in principle could also be exchanged during the ongoing operation. In the case of an impact shears whose rotor carries six chopping blade series, an implementation with two blade holders comprises accordingly three blades or blade configurations.

[0015] In the following the invention will be explained in conjunction with an embodiment example with reference to the enclosed Figures. Therein depict:

[0016]FIG. 1: a schematic partial view and examination onto a front side of an impact shears, and

[0017]FIG. 2 a schematic partial view and examination onto a front side of a further impact shears.

[0018] An impact shears 1 comprises a rotor 2 driven according to the direction of arrow depicted in FIG. 1, on whose shell surface a multiplicity of chopping blades 3 is disposed. The rotor 2 is supported in the front sides of a housing 4 serving as stator. The front sides of the housing 4 are formed by a lower yoke plate 5 and an upper yoke plate 6. Held at the stator side is a blade holder 7, which extends substantially over the entire length of rotor 2. The blade holder 7 is supported swivellably about a pivot axis S extending parallel to the rotational axis of rotor 2. For this purpose, the blade holder 7 comprises at the front side one pivot pin 8 each, which engages a horizontally extending groove 9 of the upper yoke plate 6 starting from the outer margin of the upper yoke plate 6. The blade holder 7 of this impact shears 1 comprises substantially a base body 10, approximately trapezoidal in cross section, which is the carrier of two blades 11, 12 diametrically opposing one another. The blades 11, 12 are each held on the base body 10 clamped by means of a pressure plate 13, 14 held by bolt B. The blade 11 in the representation of FIG. 1 is in its cutting position. Via a support arm 15 connected with the base body 10 are two connection noses 16, 17 for securing the blade holder 7 against a swivel motion during operation of the impact shears 1. In the position depicted in FIG. 1 the blade holder 7 is stayed with its base body 10 with the connection nose 16 on support arm 15. For this purpose a bolt, not shown in this Figure, extends through an aperture of the support arm 15 as well as such of the connection nose 16. The support arm 15, in turn, is swivellably articulated via a bolt 18 on the lower yoke plate 5. Bolt 18 has a rated breaking point such that the described staying configuration serves also as an overload safety feature during operation of the impact shears 1.

[0019] In order to supply the ground material to the screen disposed beneath the rotor 2, a guide lug 19 is disposed beneath the blade 11 which is in its cutting position.

[0020] In a further embodiment example not depicted in the Figures, the support arm 15 is articulated at the stator side via an eccentric, such that through an actuation of the eccentric an arrangement of the position of blade 11 in its cutting position for the cutting gap setting or resetting can take place.

[0021] If the blade 11 is worn out, the bolt 18 connecting the support arm 15 with the connection nose 16 is removed, the support arm 15 is pivoted down and subsequently the blade holder 7 is swivelled for example counter to the clockwise direction, such that, after this swivel motion the blade 12 is in its cutting position. This position is defined by the engagement of the connection bolt for securing in position of the blade holder 7 via the connection nose 17 with support arm 15. This blade exchange can be realized in a few minutes such that through the stand down of the impact shears 1 its productivity is hardly affected. During operation of the impact shears 1 with the blade 12 in its cutting position, it is already possible, if desired, to exchange the blade 11 against a new or newly sharpened one.

[0022]FIG. 2 depicts a further impact shears 20, which is in principle structured corresponding to the impact shears 1 of FIG. 1, and comprises a rotor 22 equipped with chopping blades 21 as well as a blade holder 23. Approximately mirror symmetrically to the vertically extending center plane of rotor 22, with the impact shears 20 a further blade holder 24 is associated, which is structured in principle corresponding to the blade holder 23 and consequently is also supported pivotably with respect to the stator—the housing. The blade holder 24 serves for a fine grinding of the material already ground by blade holder 23 which, however, has not fallen through the screen 25. The blade holder 24 also comprises two blades 26, 27 which are held in a manner corresponding to the blade holder 23 or blade holder 7 of the impact shears 1. To ensure a defined material feeding into the cutting gap of this blade holder 24 serve in each instance a flow wedge 28 or 29, which are pivotably articulated on base body 30 for the facilitated accessibility of blade 26 or 27. The blade holder 24 is secured in position torsion tight with respect to the housing via bolts 32 extending through a front side and engaging one fixing cheek 31 parallel to the rotational axis of rotor 22. These bolts 32 have a rated breaking point such that this torsion tight disposition serves simultaneously as overload safety feature.

LIST OF REFERENCE SYMBOLS

[0023]1 Impact shears

[0024]2 Rotor

[0025]3 Chopping blades

[0026]4 Housing

[0027]5 Lower yoke plate

[0028]6 Upper yoke plate

[0029]7 Blade holder

[0030]8 Pivot pin

[0031]9 Groove

[0032]10 Base body

[0033]11 Blade

[0034]12 Blade

[0035]13 Pressure plate

[0036]14 Pressure plate

[0037]15 Support arm

[0038]16 Connection nose

[0039]17 Connection nose

[0040]18 Bolt

[0041]19 Guide lug

[0042]20 Impact shears

[0043]21 Chopping blade

[0044]22 Rotor

[0045]23 Blade holder

[0046]24 Blade holder

[0047]15 Screen

[0048]26 Blade

[0049]27 Blade

[0050]28 Flow wedge

[0051]29 Flow wedge

[0052]30 Base body

[0053]31 Fixing cheek

[0054]32 Bolt

[0055] B Bolt

[0056] S Pivot axis 

1. Impact shears with a rotor equipped with individual chopping blades (3, 21) in a predetermined configuration and with a blade (11, 26) or blade configuration held in a blade holder (7, 23), fundamentally stationary relative to the rotational movement of the rotor (2, 22), and disposed at the stator side relative to the rotor (2, 22), wherein the blade holder (7, 23) is movable about an axis parallel to the rotational axis of rotor (2, 22) relative to the stator (4), characterized in that the blade holder (7, 23) carries at least two blades (11, 12; 26, 27) or blade configurations, usefully disposed at an equal angular distance with respect to one another, and rotatable about the axis extending parallel to the rotational axis of rotor (2, 22) such that each blade (11, 12; 26, 27) or each blade configuration of the blade holder (7, 23) can be brought into a cutting position cooperating with the chopping blades (3, 21) of the rotor (2, 22) and in the cutting position in each instance one blade (11, 12; 26, 27) or a blade configuration cooperates with the chopping blades of the rotor and in this position each blade (11, 26) or each blade configuration can be secured in position with respect to the cooperation with the chopping blades (3, 21) of the rotor (2, 22).
 2. Impact shears as claimed in claim 1, characterized in that the blade holder (7) at its two ends has a pivot pin (8), which is set into a horizontally extending bearing groove (9) in a front side (6) of the stator (4) and starting at the outer margin.
 3. Impact shears as claimed in claim 1 or 2, characterized in that the blade holder (7, 23, 24) can be secured such that it is torsion tight.
 4. Impact shears as claimed in claim 3, characterized in that for the securement in position of the blade holder (7, 23) in the cutting position of a blade at least one support arm (15) pivotably articulated on the stator and stayed on the blade holder, via which the forces acting onto the blade (11, 26) in its cutting position are substantially dissipated at the stator side during operation of the impact shears (1, 20).
 5. Impact shears as claimed in claim 4, characterized in that the at least one support arm (15) is swivellably articulated on the stator (4) by means of a bolt (18) having a rated breaking point.
 6. Impact shears as claimed in one of claims 1 to 5, characterized in that at the stator side a second blade holder (24) as claimed in one of claims 1 to 3 is disposed usefully for example in a configuration mirror symmetrically to the center plane of the rotor (20).
 7. Impact shears as claimed in claim 6, characterized in that with the blade holder (24) are associated fixing cheeks (31) connected torsion tight with it, into which for the torsion tight securement in position of this blade holder (24) extend bolts (32) having a rated breaking point engaging through a front side of the stator.
 8. Impact shears as claimed in claim 6 or 7, characterized in that with each blade (26, 27) of this blade holder (24) is associated a flow wedge (28, 29) usefully pivotably articulated.
 9. Impact shears as claimed in one of claims 6 to 8, characterized in that the number of blades or blade configurations on the two blade holders corresponds to the number of series of chopping blades disposed on the rotor. 